Power-transmission device.



PATENTED FEB. 19

No. 844,546. S

W. T. SEARS. POWER TRANSMISSION DEVIGE. APPLICATION FILED 00w 4 1906 Inventor Attorney I UNITED [STATES P ENT OFF CE.-

WILLARD THOMAS SEARS, F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO NILES-BEMENT-POND coMPANY, oE JERSEY CITY, NEW JERSEY.

nary construction; 9, an endwise-movable' clutch, this friction member. being POWER-TRANSMISSION DEVICE.

Specification of Letters Patent. Application filed October 4, 1906. Serial No. 387.843-

Patented reu'ia ieov.

To all whom it may concern.-

'Be it known that I WILLARD THOMAS SEARS, a citizen of the llnited States, residing at Philadelphia, Philadelphia county, Pennsylvania, have invented certain new and useful Improvements in Power-Transmission Devices, of which the following is a specification.

This invention pertains to apparatus for the transmission of power in which are involved relatively shifting toothed members for changing the rate of motionor the direction of motion or the condition from rest tomotion, and vice versa, and relates to im'' 5 P roved means for guarding against, first, the difIicult-ies of intermeshing the teeth when teeth do not happen to match tooth-spaces; second, the liability of the transmission of heavy work through teeth but partially engaged, and, third, the labor of shiftin teeth into engagement while they are un er the strain of heavy duty.

The invention willbe readily understood from the following description, taken in connection with the accompanying drawings, in which I Figure 1 is a front elevation of an apparatus embodying my invention; and Fig. 2 is a side elevation of the auxiliary driving mechanism, the. hub of the main driving-pulley and the driving-shaft appearing in vertical transverse section.

In the drawings, 1 indicates housing parts; 2, the'driving-shaft 3, the driven shaft; 4, a gear fast on the driven shaft; 5 a second but larger gear fast on the driven shaft; 6, a air of gears fast with each other and spline. .011 the driving-shaft; 7, a shifter engaging the pair of splined gears and adapted to slide them, so that its component gears may mesh with either of the mating gears, respectively, on the driving-shaft 8, a friction-clutch, which maybe of any desired or suitable ordibar to serve in engaging and disenga ing the clutch; 10, a circular friction mem er carried by the revolving pulley-of the frictionin the illustration formed by the periphery of the hub of the pulley; 11, a friction-disk-fast on the driving-shaft and of larger diameter than hub 10; 12, an arm rocking on a fixed pivot to and from friction members 10 and 11; 13, a friction-disk journaled on rocking arm 12 hub 10; 14, a friction-disk smaller than disk and adapted for peripheral engagement'with 13 and fast with it and adapted for periphtion on bar 9 in position to pass under roller 16 and of such height that when it is under the roller the rocking structure will cause hiction-disks 13 and 14 to clear friction-surfaces 10 and 11, respectively; 18, a depression in track 17 of such depth as to permit the rocker to carry the friction members into contact; 19, a'cam-lug on track 17 of such height as to move the rockingstructure farther than is necessary to relieve the contact of the friction-surfaces, and 20 a brake-shoe carried by the rocking structure and adapted to engage friction-dis 11 under the influence of cam 19.

Assume, first, that the friction-clutch is engaged, the driving-shaft in motion, and gears 6 in the neutral or disengaged position. Track portion 17 will be under the roller, and the friction members will be out of engage-' ment with each other, and the brake-shoe will be free; If now an attempt be made to slide gears 6 into engagement with one of the driven gears, an opportunity would quickly present itself for tooth ends to enter toothspaces; but,the instant this occurred the full power and speed would become transmitted to'the driven gear, and heavy working duty would thus be imposed upon teeth engaged," perhaps, but a mere fraction of their length. This often breaks teeth and always results in the mutilation of the ends .of the teeth, and in-cornpleting the enga ement of the-teeth considerable manual efiort would be required in doing so,'owing to the teeth being under full working strain.

Assume, secondly, that the friction-clutch 1s disengaged, so that its pulley may gears 6 are in neutral idle position and disre v gard for the present the auxiliary friction andbrakedevices. If an attempt be now made to shde gears 6 into engagement with one of the mating gears, the attempt may,

and is quite'apt to be, defeated by lack of register between tooth ends and tooth spaces. One of the gears must be angularly adjusted before engagement can be initiated. Therefore, as will be seen, troubles which may be of serious character are quite'likely to'arise in engaging the teeth regardless of whether the sliding gear be rotating or at rest. My present improvement, involving of the friction-clutch has cut off the power,

and normally the drivingshaft and sliding gear would come to rest; but the dropping of the roller into the depression in the clutchoperating bar has brought friction-disks 13 and 14 into frictional driving contact with friction members and 11, respectively, the result being that the loose rotating clutch-pulley 8 transrrits motion at light power and low I speed to the driving-shaft and. to the sliding gear. Whi1e the sliding gear is thus in slow rotation, an attempt may be made to shift it into engagement with one of the mating gears. If its teeth fail to enter tooth-spaces, the opportunity for entering will quickly present itself, and-the instant the engagement has been initiated then the driving-shaft and sliding gears cease rotation, as the auxiliary friction arrangement has not the power to overcome the resistance represented by the driven shaft.'-Un'der these conditions the engagement of the teeth may be oonpleted with perfect safety and with trifling effort, and when the engagementis corrplete then the friction-clutch may be thrown into" engagement, tlnis putting on the full power and releasing the auxiliary friction arrangement. Similarly, when the teeth are to be disengaged instead of the act requiring an effort corresponding'with the transnission of full power through the teeth and with danger of transmitting full power through but partially-engaged teeth the friction-clutch may be first disengaged and-then the teeth disengaged while the-gearing is at rest, the driving-shaft and sliding gears taking up very slow rotation as soon as the disengagement shall have been corrpleted.

' In some cases it may be desirable to positively arrest the motion of the gears, whether engaged or disengaged, and in such case it is y necessary after disengaging the friction-clutch to move the clutch-operating bar somewhat farther, and thus cause lug 19 to apply the brake-shoe to the friction-disk on the driving-shaft. v 4 The difficulties and dangers which have been pointed out as incident to the employment of sliding toothed gears in transmission devices have long been recognized as present in most every character of transmission device involving toothed members of one form or another to be enga ed and disengaged,

and it is thought that t e present invention becomes of availability in connection with most any such shifting tooth device. Any usual or suitable means may be employed for actuating the shifter and the clutch-operat in bar.

claim-- 1. Power-transmission apparatus comprising a pair of toothed members, means for shifting one of said members into and out of engagement with the other, a rotary drivin device for transmitting the power to an through the toothed members when engaged,

means for connecting and disconnecting said rotary drivin device to and from one of said toothed mem ers, friction transmission-gearing disposed between said rotary driving member and one of said toothed members,

and means for throwing said friction-gearing into and out of action, combined substantially as set forth. p

2. Power-transmission apparatus comprising a pair of toothed members, means for shifting one of said members into and out of engagement with the other, a rotary driving device for transmitting the power to and through the toothed members when engaged, means for connecting and disconnecting said rotary drivin device to and from one of said toothed mem ers, friction transmission-gearing disposed between said rotary driving member and one -of said toothed members and arranged to transmit motion to one of said toothed members at abnormally low speed, and means for throwing said frictiongearing into and out of action, combined. substantially as set forth.

3. Power-transmission apparatus comprisin a pair of toothed members, means for shifting one of said members into and out of engagement with the other, a rotary driving device for transmitting the power to and through the toothed members when engaged,

means for connecting and disconnecting said v rotary drivin device to. and from one of said ICC toothed mem ers, frictiontransmission-gear- WILLARD THOMAS Witnesses:

Anonmam M. O'BRIEN SAMUEL O-KANE SEARS. 

